C/1999 S4 (LINEAR)
{{short description|Hyperbolic comet}}
{{For|other comets of the same name|List of comets discovered by the LINEAR project}}
{{Infobox comet
| name = C/1999 S4 (LINEAR)
| image = CometLinear.jpg
| caption = Hubble image of C/1999 S4 disintegrating on 5 August 2000
| discovery_ref = {{r|MPEC_1999-T02}}
| discovery_site = Socorro, New Mexico
| discovery_date = 27 September 1999
| designations = CJ99S040{{r|MPEC_1999-T02}}
| orbit_ref = {{r|barycenter|jpl}}
| epoch = 13 February 2000 (JD 2451587.5)
| observation_arc = 300 days
| obs = 1,230
| perihelion = 0.765 AU
| aphelion = ~1400 AU
| semimajor = ~700 AU
| period = ~18,700 years
| eccentricity = 1.00010
| inclination = 149.38°
| asc_node = 83.181°
| arg_peri = 151.05°
| tjup =
| Earth_moid = 0.174 AU
| Jupiter_moid = 0.802 AU
| physical_ref = {{r|Altenhoff_2002|cometography}}
| dimensions = {{cvt|0.9|km|mi}}
| M1 = 9.6
| M2 =
| magnitude = 6.6–6.8
(2000 apparition)
| last_p = 26 July 2000
| next_p =
}}
C/1999 S4 (LINEAR) was a hyperbolic comet discovered by the Lincoln Near-Earth Asteroid Research survey on 27 September 1999.{{r|MPEC_1999-T02}}
Physical properties
Its nucleus was estimated to be about 0.9 km in diameter.{{r|Altenhoff_2002}} Before the comet broke up, the (dust and water) nucleus erosion rate was about 1 cm per day.{{r|Altenhoff_2002}} The comet brightened near 5 July 2000, and underwent a minor fragmentation event.{{r|Weaver_2000}} The comet brightened again around 20 July 2000, and then disintegrated.{{r|Villard_2000}} The published optical and most radio data support that the main nuclear decay started 23 July 2000.{{r|Altenhoff_2002}} The dust cloud expanded at about {{cvt|20|m/s|ft/s}} while the fragments expanded at around {{cvt|7|m/s|ft/s}}.{{r|Altenhoff_2002}} Other comets are known to have disappeared, but Comet LINEAR is the first one to have been caught in the act.{{r|Kidger_2000}}
Orbit
The orbit of a long-period comet is properly obtained when the osculating orbit is computed at an epoch after leaving the planetary region and is calculated with respect to the center of mass of the Solar System. Using JPL Horizons, the barycentric orbital elements for epoch 2010-Jan-01 generate a semi-major axis of 700 AU, an aphelion distance of 1400 AU, and a period of approximately 18,700 years.{{r|barycenter}}
The comet made its closest approach to the Earth on 22 July 2000, at a distance of {{convert|0.372|AU|e6km|abbr=unit}}.{{r|jpl}} It came to perihelion on 26 July 2000, at a distance of {{convert|0.765|AU|e6km|abbr=unit}} from the Sun.{{r|jpl}}
References
{{Reflist|refs=
| author1= W. J. Altenhoff
| author2= F. Bertoldi
| author3= K. M. Menten
| author4= A. Sievers
| author5= C. Thum
| author6= E. Kreysa
| display-authors= 3
| title= Radio continuum observations of Comet C/1999 S4 (LINEAR) before, during, and after break-up of its nucleus
| url= https://www.aanda.org/articles/aa/pdf/2002/31/aah3432.pdf
| journal= Astronomy & Astrophysics
| year= 2002
| volume= 391
| issue= 1
| pages= 353–360
| bibcode= 2002A&A...391..353A
| doi= 10.1051/0004-6361:20020783
| doi-access= free }}
| author1= Horizons output
|title=Barycentric Osculating Orbital Elements for Comet C/1999 S4 (LINEAR)
| url= http://ssd.jpl.nasa.gov/horizons.cgi?find_body=1&body_group=sb&sstr=C/1999+S4
| access-date= 1 September 2011 }} (Solution using the Solar System Barycenter and barycentric coordinates. Select Ephemeris Type:Elements and Center:@0)
| author1= G. W. Kronk
| title= C/1999 S4 (LINEAR)
| url= http://cometography.com/lcomets/1999s4.html
| website= Cometography.com
| access-date= 7 January 2025 }}
| title= C/1999 S4 (LINEAR) – JPL Small-Body Database Lookup
| url= https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=1999S4
| website= ssd.jpl.nasa.gov
| publisher= Jet Propulsion Laboratory
| access-date= 1 September 2011 }}
| author1= M. Kidger
| title= Comet LINEAR: Going, Going... But Not Quite Gone!
| url= http://www.ing.iac.es/PR/press/ing300.html
| website= The Isaac Newton Group of Telescopes
| date= 4 August 2000
| access-date= 1 September 2011 }}
| author1= B. G. Marsden
| title= MPEC 1999-T02: Comet C/1999 S4 (LINEAR)
| url= http://www.minorplanetcenter.org/mpec/J99/J99T02.html
| website= www.minorplanetcenter.net
| publisher= Minor Planet Center
| date= 1 October 1999
| access-date= 1 September 2011 }}
| author1= R. Villard
| author2= M. Purdy
| title= Hubble Discovers Missing Pieces of Comet LINEAR
| url= http://hubblesite.org/newscenter/archive/releases/2000/27/text/
| website= HubbleSite.org
| date= 7 August 2000
| access-date= 4 September 2011
| archive-date= 2 August 2007
| archive-url= https://web.archive.org/web/20070802142658/http://hubblesite.org/newscenter/archive/releases/2000/27/text/
| url-status= dead }}
| author1= D. Weaver
| author2= M. Purdy
| title= Hubble Sees Comet Linear Blow its Top
| website= HubbleSite.org
| url= http://hubblesite.org/newscenter/archive/releases/2000/26/text/
| date= 28 July 2000
| access-date= 4 September 2011
| archive-date= 21 September 2007
| archive-url= https://web.archive.org/web/20070921001237/http://hubblesite.org/newscenter/archive/releases/2000/26/text/
| url-status= dead }}
}}
External links
- {{JPL Small Body|id=1000273}}
- [http://www.aerith.net/comet/catalog/1999S4/1999S4.html C/1999 S4 ( LINEAR )] – Seiichi Yoshida @ aerith.net
- [https://web.archive.org/web/20111020051056/http://www.eso.org/public/news/eso0026/ The VLT Observes Comet LINEAR's "Shower"] (6 August 2000)
- [https://science.nasa.gov/science-news/science-at-nasa/2000/ast31jul_1m/ Comet LINEAR continues to disintegrate and could disappear completely within a few days] {{Webarchive|url=https://web.archive.org/web/20200727061417/https://science.nasa.gov/science-news/science-at-nasa/2000/ast31jul_1m/ |date=2020-07-27 }} (31 July 2000)
{{Comets}}
{{Authority control}}
{{DEFAULTSORT:LINEAR, 1999 S4}}